The western deermouse or western deer mouse is a rodent native to North America. It is widespread throughout the western half of the continent, mainly in areas west of the Mississippi River.

Peromyscus maniculatus is a rodent native to eastern North America. It is most commonly called the eastern deer mouse; when formerly grouped with the western deer mouse, it was referred to as the North American deermouse and is fairly widespread across most of North America east of the Mississippi River, with the major exception being the lowland southeastern United States.